Electrosurgical apparatus for delivering RF and/or microwave energy into biological tissue

An electrosurgical instrument for delivering electromagnetic energy to biological tissue, the instrument comprising an active tip having an electrically conductive protective hull mounted on an underside thereof. The hull has a smoothly contoured convex undersurface, and is formed as a shaped piece of electrically conductive bio-compatible material having a low coefficient of friction with biological tissue (e.g. stainless steel) which has the dual function of (i) physically protecting tissue that lies underneath the active tip, and (ii) providing an electrical connection between a coaxial feed line and the active tip.